Abstract To successfully and efficiently dialyze, patients with end-stage renal disease (ESRD) patients must have a reliable conduit to access the vasculature (vascular access), either an arteriovenous fistula (AVF) or arteriovenous graft (AVG). Despite national consensus vascular access guidelines that strongly recommend preferential placement of AVFs, 80% of ESRD patients initiate HD with a central vein catheter (CVC). Such patients? the focus of our grant?require timely vascular access planning and surgery once they have initiated HD to ensure a permanent AVF access is placed. Disparities in AVF use between blacks and whites begin at HD initiation and increase progressively following AVF creation, such that at 1 year it is 58.8 vs 67.8%, respectively, which translates to 5,000 excess deaths among blacks annually. The proposed grant will investigate patient, provider, and system factors contributing to racial disparities in AVF use. Three major surgical processes of care determine AVF use in hemodialysis patients. First, an AVF needs to be created in the patient who initiates HD with a CVC. Second, the new AVF has to mature adequately to be used for HD. Third, once the AVF has matured, it needs to maintain long-term patency for dialysis, often requiring access interventions such as angioplasty, thrombectomy, or surgical revision. Aim 1 will use qualitative research to elucidate views on AVFs and barriers to AVF processes of care among black and white patients at various stages of dialysis care. We will use semi-structured interviews of black and white dialysis patients and their providers (surgeons, nephrologists, and dialysis nurses) to identify common themes regarding the decision- making around initial AVF creation and subsequent interventions. Aim 2 will use quantitative research to determine whether there are racial disparities in the key processes of care required to achieve and maintain AVF use for dialysis among patients initiating HD with a CVC. We will retrospectively query the national USRDS database of incident HD patients to determine whether one or more of the 3 key AVF surgical processes of care differ between blacks and whites. In parallel, we will prospectively collect more granular data on these processes of care in patients initiating HD at a large dialysis center. Aim 3 will determine the relationship between system level factors and AVF processes of care. Aim 4 will administer validated surveys to incident black and white hemodialysis patients scheduled for AVF surgery over a 4-year period at UAB, and quantify potential patient barriers to and facilitators of AVF use. We will then determine which specific patient, provider, and system factors are associated with differences in AVF processes of care (identified in Aim 2) by prospectively collecting vascular outcomes data for this UAB population. Finally, we will use mediational analysis to identify the most important modifiable patient, provider, and system factors related to AVF use among black dialysis patients. These factors will be used to develop a future multi-level interventional trial to evaluate whether addressing specific barriers can reduce racial disparities in AVF use.